1. Field of the Invention
The present invention relates to a data processing apparatus such as an image reading apparatus or an image forming apparatus or the like devices.
2. Prior Art
Conventional image reading apparatuses can be roughly classified into an ADF (automatic document feeder) type, a flat bed type, and a composite type. FIG. 57 in the attached drawings illustrates an image reading apparatus of the ADF type. As shown, the image reading apparatus of this type comprises a hopper 74 onto which documents or sheets to be read are set, a reading head 73 for reading information on the document, and a stacker 75 onto which the documents are discharged after they are read. A plurality of documents can be set onto the hopper 74 and are automatically and successively conveyed through the image reading apparatus by conveying rollers 76. The reading head 73 such as an image sensor, and information recorded on the document can be read by the reading head 73. The documents are discharged onto the stacker 75. As described above, the image reading apparatus of the ADF type can operate automatically and continuously, and the efficiency of the operation is higher than that of the other type of image reading apparatuses. Therefore, the image reading apparatus of the ADF type is suited for the applications where large amounts of documents must be read at high speed.
An image reading apparatus of the flat bed type is shown in FIG. 58 in the attached drawings. The image reading apparatus of this type is provided on its upper surface with a flat bed unit having a reading window 72, and a reading head 73 is arranged within the reading window 72. A cover 76 is attached to the flat bed. To read the documents using the image reading apparatus of the flat bed type, the documents are set onto the reading window 72. When the reading operation is started, the reading head 73 moves to scan the document, whereby information on the document is read. To read another document following thereto, the document that has been read is removed from the reading window 72, and a new document is placed on it.
The image reading apparatus of the flat bed type requires replacement of the document after every reading operation, and is not suited for reading the documents at high speed and, hence, does not have a high reading efficiency. However, it has a simple structure and a low cost because it does not have a document feeding mechanism, so the image reading apparatus of the flat bed type has been widely used for the applications where large amounts of documents need not be read at one time. The documents such as books cannot be set to the hopper and cannot be read by the image reading apparatus of the ADF type, but they can be read by the image reading apparatus of the flat bed type.
There is proposed an image reading apparatus of a combination of the ADF type and the flat bed type, by which it is possible to select the reading operation depending upon the kind of documents to be read.
In addition, the data processing apparatus in the form of a printer comprises a hopper for setting the printing papers and a stacker onto which the papers will be discharged after printing. Some printers have a plurality of hoppers onto which papers of different sizes can be set to cope with a plurality kinds of the printing papers.
The conventional equipment, however, has problems as described below. In the image reading apparatus of the ADF type or in the printer equipped with the hopper and the stacker as shown in FIG. 57, the hopper and the stacker project from its casing to the exterior thereof. Therefore, much space must be maintained for holding them, so that the hopper and the stacker do not interfere with other apparatuses.
Recently, it has been urged to efficiently utilize the space in offices, and available space for setting office equipments such as personal computers, keyboards, image reading apparatuses and/or printers are decreasing. To meet this demand, equipments are becoming smaller in size, but there are limitations. In particular, the hoppers and stackers of the image reading apparatuses and printers have their sizes determined depending upon the sizes of the documents (printing papers), and cannot be made small.
EP-Al-0621719, filed by the same assignee as for the present case, discloses a data processing apparatus having a box-shaped casing having parallel and horizontal cavities and a hopper table arranged in the upper cavity. The hopper table has a hopper onto which a plurality of sheets can be set and a reading head, and the lower cavity of the casing serves as a stacker. Sheet conveying rollers are arranged for conveying the documents from the hopper through the reading head to the stacker. A plurality of documents can be handled at a time, and yet, the hopper and the stacker do not project from the casing. Therefore, this apparatus can solve the above described problems.